chemistry

Sulfur compounds

Sulfur compounds is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Sulfur compounds rather than just read about it. In short: Sulfur compounds are chemical compounds formed with the element sulfur (S). Common oxidation states of sulfur range from −2 to +6.

Key takeaways

Sulfur compounds belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Sulfur compounds to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Sulfur compounds from memory before moving on to harder problems.

Reference excerpt

Sulfur compounds are chemical compounds formed with the element sulfur (S). Common oxidation states of sulfur range from −2 to +6. Sulfur forms stable compounds with all elements except the noble gases.

Electron transfer reactions

Sulfur polycations, S82+, S42+ and S192+ are produced when sulfur is reacted with oxidising agents in a strongly acidic solution. The colored solutions produced by dissolving sulfur in oleum were first reported as early as 1804 by C.F. Bucholz, but the cause of the color and the structure of the polycations involved was only determined in the late 1960s. S82+ is deep blue, S42+ is yellow and S192+ is red. Reduction of sulfur gives various polysulfides with the formula Sx2-, many of which have been obtained in crystalline form. Illustrative is the production of sodium tetrasulfide:

4 Na + S8 → 2 Na2S4 Some of these dianions dissociate to give radical anions, such as S3− gives the blue color of the rock lapis lazuli.

This reaction highlights a distinctive property of sulfur: its ability to catenate (bind to itself by formation of chains). Protonation of these polysulfide anions produces the polysulfanes, H2Sx where x = 2, 3, and 4. Ultimately, reduction of sulfur produces sulfide salts:

16 Na + S8 → 8 Na2S The interconversion of these species is exploited in the sodium–sulfur battery.

Hydrogen sulfide

Treatment of sulfur with hydrogen gives hydrogen sulfide. When dissolved in water, hydrogen sulfide is mildly acidic:

H2S ⇌ HS− + H+ Hydrogen sulfide gas and the hydrosulfide anion are extremely toxic to mammals, due to their inhibition of the oxygen-carrying capacity of hemoglobin and certain cytochromes in a manner analogous to cyanide and azide.

Oxides The two principal sulfur oxides are obtained by burning sulfur:

S + O2 → SO2 (sulfur dioxide) 2 SO2 + O2 → 2 SO3 (sulfur trioxide) Many other sulfur oxides are observed including the sulfur-rich oxides sulfur monoxide, disulfur monoxide, disulfur dioxides, and higher oxides containing peroxo groups.

Halides Sulfur reacts with fluorine to give the highly reactive sulfur tetrafluoride and the highly inert sulfur hexafluoride. Whereas fluorine gives S(IV) and S(VI) compounds, chlorine gives S(II) and S(I) derivatives. Thus, sulfur dichloride, disulfur dichloride, and higher chlorosulfanes arise from the chlorination of sulfur. Sulfuryl chloride and chlorosulfuric acid are derivatives of sulfuric acid; thionyl chloride (SOCl2) is a common reagent in organic synthesis. Sulfur halides are precursors to a variety of metal complexes.

Pseudohalides Sulfur oxidizes cyanide and sulfite to give thiocyanate and thiosulfate, respectively.

Metal sulfides Sulfur reacts with many metals. Electropositive metals give polysulfide salts. Copper, zinc and silver are tarnished by sulfur. Although many metal sulfides are known, most are prepared by high temperature reactions of the elements. Sulfide minerals contain the sulfide (S2-) or disulfide (S22-) anions. Typical examples are:

Acanthite Ag2S Chalcocite Cu2S Galena PbS Sphalerite ZnS Chalcopyrite CuFeS2 Millerite NiS Cinnabar HgS Stibnite Sb2S3 Pyrite FeS2 Molybdenite MoS2

Organic compounds

Some of the main classes of sulfur-containing organic compounds include the following:

Thiols or mercaptans (so called because they capture mercury as chelators) are the sulfur analogs of alcohols; treatment of thiols with base gives thiolate ions. Thioethers are the sulfur analogs of ethers. Sulfonium ions have three groups attached to a cationic sulfur center. Dimethylsulfoniopropionate (DMSP) is one such compound, important in the marine organic sulfur cycle. Sulfoxides and sulfones are thioethers with one and two oxygen atoms attached to the sulfur atom, respectively. The simplest sulfoxide, dimethyl sulfoxide, is a common solvent; a common sulfone is sulfolane. Sulfonic acids are used in many detergents. Compounds with carbon–sulfur multiple bonds are uncommon, an exception being carbon disulfide, a volatile colorless liquid that is structurally similar to carbon dioxide. It is used as a reagent to make the polymer rayon and many organosulfur compounds. Unlike carbon monoxide, carbon monosulfide is stable only as an extremely dilute gas, found between solar systems. Organosulfur compounds are responsible for some of the unpleasant odors of decaying organic matter. They are widely known as the odorant in domestic natural gas, garlic odor, and skunk spray. Not all organic sulfur compounds smell unpleasant at all concentrations: the sulfur-containing monoterpenoid (grapefruit mercaptan) in small concentrations is the characteristic scent of grapefruit, but has a generic thiol odor at larger concentrations. Sulfur mustard, a potent vesicant, was used in World War I as a disabling agent. Sulfur–sulfur bonds are a structural component used to stiffen rubber, similar to the disulfide bridges that rigidify proteins. In the most common type of industrial "curing" or hardening and strengthening of natural rubber, elemental sulfur is heated with the rubber to the point that chemical reactions form disulfide bridges between isoprene units of the polymer. This process, patented in 1843, made rubber a major industrial product, especially in automobile tires. Because of the heat and sulfur, the process was named vulcanization, after the Roman god of the forge and volcanism.

See also Category:Sulfur compounds Oxygen compounds Selenium compounds Phosphorus compounds Chlorine compounds

References

Illustrations

Worked examples

Example 1 — a first encounter with Sulfur compounds

Start with the simplest possible case. Write down what Sulfur compounds claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Sulfur compounds before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Sulfur compounds ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Sulfur compounds

In research: Sulfur compounds appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Sulfur compounds in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Sulfur compounds is common in secondary-school and first-year university syllabi. It links to neighbouring topics Chemical compounds by element, Sulfur, Sulfur compounds, so understanding it makes those chapters shorter.
In everyday life: Look for Sulfur compounds outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Sulfur compounds in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Sulfur compounds means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Sulfur compounds out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Sulfur compounds in simple terms?

Sulfur compounds are chemical compounds formed with the element sulfur (S). Common oxidation states of sulfur range from −2 to +6.

Why does Sulfur compounds matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Sulfur compounds?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Sulfur compounds.